Does anybody know the difference between a NNA4400EA-E and a NNA4400BA-E? And can the former be used in a V12 6.0 XJS instead of the later?

 

i cant help much , but i do know the GM 4L80E is a great transmission. for the money cant be beat.
the 4L60E is good , but the 80 is bomb proof! i have a big GM suburban diesel with the 80 and its has never been any problems 200K miles!

some times if you have both in front of you side by side a close examination would help a lot!
ron

 

The NNA4400EA E (exchange) is fitted to the 4.0 Supercharged XJ sedan (six cylinder) and the NNA4400BA E (exchange) is fitted to BOTH the 6.0 XJ-S and the XJ12 sedan (V12).

I would guess the bell housing mount pattern would be different. I have never attempted to interchange the 6 and 12 cylinder gearboxes.

good luck.

bob

 

I don't think the bellhousing pattern is different, as the XJR has an adapter plate between it and the block on the 6 cylinder. It's clearly the V12 pattern, as the starter bumpout is on the wrong side and is blanked off on the XJR

 

The transmission themselves are most likely identical but the torque converter on the I6 will likely have a higher stall speed. The trans and converter are a package and thus would have a different part number. The I6 with its higher idle and taller 3.27 gears would most likely use a higher stall converter as is typical for 6 cylinders to increase responsiveness and reduce idle creep. The V12 with it's lower idle speed and prodigious low end grunt would likely have a low stall for refinement and fuel economy. Thats my theory. Putting the I6 converter in the V12, if it bolts up, would create a more slushy auto box experience but might also increase acceleration at the expense of fuel economy.

 

My theory is that the XJR transmission is designed to start off in 1st gear in both normal and sport modes. That's how my XJR operated, at least.

The V12 version is designed to start off in second gear unless sport mode is selected.....in which case it starts off in first gear

Cheers
DD

 

Wouldn't that depend on the controller, not the transmission itself? The XJR and XJS 6.0 controllers have different part numbers.

 

Ahhh. Could be.

I was thinking they had different valve bodies

Cheers
DD

 

Those are the same.

 

Running this trans in my '89 through an aftermarket TCU and it definitely starts off in 1st.

 

I have three of this transmissions. One is from xj40(81) then X300 and XJR6. XJR6's has blue painted torque converter and different rear end of the body. X300's has reinforced TC with steel plate. I did not find another differences niether internal nor outside .

 

But none of those are the V12 unit are they or is the XJ40 a V12? Also when you say the rear end of the body is different, would that affect interchangeability?

 

Thanks for the info (everybody), quick question, what do you mean exactly by " if it bolts up". Would the torque converter be different physically possibly?

 

The way the converter bolts to the flex plate may not be the same. Just swap he converter or re-drill the flexplate.
If the center bore of the converter is indexed into the flex plate you have some margin for imprecision, if not then the bolt holes will need to be exact.
See this. https://www.monstertransmission.com/...les_ep_74.html

 

Ok so the converter is blue, that is color coding and the way the factory makes sure they dont get mixed up during part selection. What do you mean "diffrent rear end of the body"

 

Rear end. I mean rear alloy extender. They have different connection to the trans mount.

 

Are there gear ratios of these transmissions published anywhere?

 

I think I have found the answer, the ratios are inherent to the transmission design i.e. all 4L80s have the same ratios, unlike a manual box. So that can't be the difference.

 

The ratios for 4L80 are the same as the TH400
1st 2.48
2nd 1.48
3rd 1.00
4th 0.75
R 2.07

 

You do not say what you are trying to accomplish.

Are you replacing the trans in your car or are you upgrading?